Circuit breaker



April 7, w31.

L. T. JNE; 1,799,689

C IRCUIT BREAKER Filed oct. 7, 1929 Z INVENTOR.

ATTORNEY.

Patented Apr. 7,l 1931 UNITED STATES PATENT OFFICE f LLOYD T. JONES, F BERKELEY, CALIFORNIA CIRCUIT BREAKER Application filed october 7', 1929. serial no. 397,889.

mally between 5,000 and 25,000 volts. This voltage is acquired by means of suitable trans formers. y Y,

As luminescent tubes containing such gases ,15'as neon, argon, helium, or the like are now coming into use for interior ldecorative pur poses and it i-s apparent that perfect protection from-electrical shock by contact with the terminals of a tube that has failed to operate, or which is operating at an undulyhigh voltage is of vital importance. Since the breaking of the secondary orhigh potential circuit enhances rather than re-V Y moves the hazard, it is the primary object of this invention to provide a circuit breaker that is actuated by the excess voltage in the secondary circuit, as caused by a defective tube, to cause a permanent break in the primary circuit.

Another object of the invention is to provide means whereby the circuit breaker may.

be manually actuated to close the break in the secondary circuit when the defective tube has been replaced so that the new tube may be easily and readil placed in service. It is desirable that sai means be of vsuch a simple nature that in localities where the manufac-V turers service is not readily available, the ordinary layman should be able to replace the tube and reset the device even though he may not possess any technical knowledge of electricity.

A further object of this invention isto provide a circuit breaker of the character set forth that will be superior in the point of simplicity, inexpensiveness of construction, positiveness of operation, and facility and convenience in use and general etliciency.

With the foregoing and other objects in view, which will be made manifest in the folstructure.

lowing detailed description and specifically pointed out in the appended claims, reference is had to" the accompanying drawings for the illustrative embodiment of the. invention, wherein:

Fig. l is a perspective view of al complete luminescent tube installation, and illustrating the circuit breaker of my invention.

Fig. EZ is a top plan sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is front sectional view taken on the line 3--3 of Fig. 2 and with the luminescent ,tube removed.

' Fig. et is a wiring diagram showing the invention as connected.

Y Y Flg. 5 is a detail perspective view showing the manner in which the ends of the circuit breaker are hingedly secured to a supporting -electric thermostatic circuit breaker of my Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the various` figures described above adequately illustrate my invention, and the following detailed dev scription is commensurate with the above v mentioned drawings in enabling an artisan to construct and assemble the constituent parts of the same. e

The device involves in its general adapta- SQ 'tion a receptacle designated as an entirety by the reference numeral 5.' Said receptacle comprises a rectangular hollow box like body 6 havinga removable side plate 7 Sockets 8 and 9 are formed in the body of the recepta- 85 cle 5 Y at the corners thereof and extend through said receptacle and are terminated at one end thereof by vthe plate 7. Disposed within the sockets 8 and 9 andpositioned at the closed ends thereof, are resilient contacts 1l and l2 formed of a strip of sheet metal bent nto substantially a T shape.

`Numeral 13 indicates a transformer which is postioned within the hollow receptacle 5 and connected to the contacts l1 and l2 and 95 a source of electricity, it being preferable that the respective sizes of the interior of the box and the transformer be such as to provide a substantially snug fit so as to prevent the transformer from moving about in said boX.

A tube filled with gas such as neon at reduced pressure, is indicated at `16 and is formed in 'ends thereof. It will now be seen that by inserting the ends of the tube 16 in the sockets 6 and 9, the jack plugs 17 will be engaged by the resilient contacts 11 and 12, thereby connecting the electrodes 17 with the transformer 13, which is connected to a source of electricity, causing ja discharge from each electrode and thereby illuminating the gas in the tube.

Viewing Fig. 2 of the drawings, it will be seen that the size of the sockets 8 and 9 are.

such as to provide a relatively snugvlit with ends of tube 16 and in this manner the said tube is held substantially rigid with respect to the receptacle 5.

Means are provided for automatically breaking the circuit tothe tube 16 when the tub.:l becomes defective in any manner. Said means comprises a circuit breaker comprising a curved strip ol' himetallic sheet metal 2l commonly known as thermostatic metal; The therlnostatic strip 2l is hingedly mounted at its opposite endsin terminal supports 22 which are attacl'iedtothe "core of transforn'ier 13.. A terminal 23 anda contact 24, consists of screw threaded -contact --screws which extend through threaded openings in a plate of insulating material andalfso attached to the transformer' i3. Normally the terminal 23 is adjusted so that the endtthereof is spaced from the strip 2l and the contact 24 is adjusted so as to contactl with said strip as is clearly shown in Fig.

ln Fig. :Bof the drawings there is shown the preferable method of hinging the strip 21 to the terminal supports 22. This consists in forming a slot in each 4end of the strip 21 which slotlits loosely in a corresponding V notch 31 formed in each of the terminals 22. 'hepurpose ofthis construction will be hereinafter set forth. e Y

Viewing Fig. 4 the transformer 13 consists of -aprimarywinding and a secondary Winding 33, Thewinding 32 is connected to a wire 34 leading to a source of alternating current supply. A second wire 36 connects with one of the two terminals l22 which are in electrical contact with and support the themostatic strip 21; Y

The thermostatic strip 21 is composed of a thin strip of brass 37Y and a similar strip of invar metal 38 welded to form a single piece in such a manner as to have one face of brass and the opposite lface of ,invar metal. -The Vlumine lcent tube 16, h'

.A 1,799,6sa

in curvature will cause the strip to move suddenlyl t'o a new position as indicated by the p perature has returned to normal. VVIn movingv from the solid line position to the dotted line position the strip 21 is not stressed beyond itsv elasticl limit and therefore suffers no permanent change inshape.- (donstequently, it may be returned toitsoriginal position. Means are provided for returning thestrip 21to its original position :said means comprising av button 41 slidably mounted in. a socket 42 formed in one side'of thecasing 6 so as to extend transversely ofthe strip 21. A coil compression yspring 43 normally holds the button 41 in extended position as clearly shown in Fig. 2. The motion of the button 411is limited to that suflicient to return the` strip to its ori final solid line position.

In Fig. 4 the secondary 33 of the transformer 3 is connecter to the terminalsof the a wire 42 which connects to one end of sai tube, and tothe other end of. said tube through a wire 43 which connects with the contact 24 which in turn connects with the strip 21 and through a wire 44 connecting the terminal 22 with the end of said tube. A spark gap to the ther- .Y

mostatic metal isplaced in parallel with the luminescent tube by means` of the wire 43 100 which connects to the contact 24 and a second wire 46 which connects to the terminal 23 spaced from the strip 21. The transformer shown in the drawings is Vof the type known `as the auto transformer, having one end of the primary and secondary windings connected as by a wire 51. Should both ends of the secondary be free a second terminal similar to the terminal 23 is provided for connecting to `the other end of said secondary winding. A

The luminescent tube 16 is filled with gas at or near itsbest conducting state. yThe length of spark formed by the strip 2 1 and' the terminal 23 is adjusted sothat theoperating voltage of the tube is not sufficient to bridge the gap. Should the voltage operating the tube becomey excessive either because of increasing yacuum within the tube or because of breakage of the tube a spark will occur betweenthe strip 21 and the .terminal 23 and the heat thus given the thermostatic strip, will cause it to move to the dotted line position shown in Fig. 4 breaking the primary circut at 24.

It is of vital importance that the strip 21 have a compound curvature such as that illustrated. Should the strip have a simple curve and if it is longer than the distance-between the supporting terminals 22 the strip in moving will pass from a convex inward to alter its angular position of contact with the terminals 22. It will thus fail to accomplish its purpose of providing a permanent break in the primary circuit unless such provision for angular displacement at the ends be made.

When the thermostatic strip 21 possesses -a compound curvature and is properly hinged at the ends it may be caused by rise in temperature. to pass suddenly and permanently from the full line position in Fig. 4

Vto the dotted line position. It is qcarefully adjusted so that atmospheric temperatures will not cause it to move and when once moved it will not return to its original position although the temperature returns to normal. v

In the drawings the spark gap terminal 23 is positioned so that the heat w1l1 be applied at apoint where the metal whose expansion coeiiicient is the greater lies on the convex side of the center curve in the thermostatic strip 21. When the heat is applied at this point the strip will movefaster than when the heat is applied at a/point where the opposite curvature exists. This has been proven by careful experiment.-

From the foregoin it is thought that the. l construction, usc) an many advantages of.

the herein `descri ed circuit breaker will be adequately understood. I t will be further. understood that certain material alterations in the construction may be effected without having a deleterious effect upon the eiiciency of the device.j The minordetails of construction will at all times of course be performed within the scope and spirit of the sub-joined claims.

' Claims: 1 1. In an'automatic circuit breaker, in combination, a stationary contact member, a movable contact member normally contacting with said stationary contact, comprising a strip of thermostatic metal hingedly mounted at its ends, and a spark terminal :s aced from said movable contact member an forming a spark gap therebetween.

2. In an automatlccircuit breaker, in Combination, a stationary contact member, a movable thermostatic contact member, com rising a strip formed of two strips of'metal aving dierent coeicients of linear e ansion, means for' hinging said strip at the en thereof, and a .spark terminal spaced from saidstrip and positioned so as to'form asp'ark 3. In anautomatic-circuit breaker, coming a strip"formed of two strips of metal having dilerent coeicents of linear expansion,

nature.

p between said terminal and the strip'of l metal. Y

` from said strip and positioned so as to form a spark gap between said terminal and the strip of metal.

4. In an automatic circuit breaker, in combination, a stationary contact member, a movable thermostatic contact member, com rising a strip formed of two strips of metal aving different coeiicients of linear expansion, sa1d strip being formed with a compound curvature, means for hinging said strip at the ends thereof, and a spark 'terminal spaced from said strip and positioned so as to form a spark gap between said terminal and the strip of metal, and at a point where said strip of metal is concave wit respect to the metal portion having the lower coeilicient of expanslon.

5. In an-automatic circuit breaker, in combination, a stationary contact member, a movable thermostat-ic contact member com rising a strip formed of two strips of metal aving different coeflicients of linear expansion and formed with a compound curvature, said strip being' formed at each end with a slot vfor engaging corresponding V notches formed in terminal, members provided for hingedly supporting said ends, a spark terminal spaced from said strip and positioned so aS to form a spark gap between said .terminaland the strip of metal, whereby a spark from said terminal will cause said thermostatic strip to move from said stationary contact, and manually operated means for engaging said strip and reen ging said contacts.

In testimony whereof I have aixed my sig- Y I LLoYD'nJoNEs-j 

